The present invention relates to monitoring equipment for the safety devices used in vehicles when driving in reverse which comprise at least two transmitter/receiver pairs that are mounted on the back of the vehicle. The monitoring equipment operates by reflecting sound off any nearby object using a known method that is also referred to as echo sounding. Each transmitter/receiver pair is coordinated with an electroacoustic transducer.
Safety devices for driving a vehicle in reverse, such as these mentioned above, are known from the journal "Elektronik" 22, 10/31/1986, pages 48 and 50. In these sonic warning devices, automatic test programs indicate a malfunction of the electronic evaluation circuit. These programs, however, cannot detect faulty operation of the safety device that is caused by environmental conditions that act upon the sensors, i.e., the electroacoustic transducers. Thus, the present invention uses simple monitoring equipment to indicate whether the foregoing kind of safety device for driving a vehicle in reverse malfunctions during operation and whether the malfunction is caused by component failure or by soiling, wetting, icing, etc. of the transducers.